wet skim v's dry skim

[heller792]

just wondering whats the best and people opinions on it. Ive added a ball valve to my skimmer so i can get a really think gunky skim or i can get a light watery skim.


Dave


ps sorry to ask this, its prob been asked a thousand times.

 

[BowieReefer84]

I like it wet.

However, if you skim really wet you are losing salt slowly over time. You must account for this with water changes or something.

 

[lordofthereef]

You will have varying viewpoints on this. I have even heard that over X amount of time, each method ends up removing the same amount of waste.

I actually rather enjoy a very wet skim as a means of water changes. On my 150g system I would do 5 gallons a day this way.

 

[lordofthereef]

I like it wet.

However, if you skim really wet you are losing salt slowly over time. You must account for this with water changes or something.

Regardless of skimming methods, the best rule of thumb, IMO, is to replace the skimmed volume of water with clean salt water.

 

[TrojanScott]

It's just that... opinion. Some say really no difference or it doesn't matter. I try to wet skim. Only downside is emptying the collection cup more often. Up to you really.

 

[jimmy frag]

dosnt really answer your question does it. i have asked before and dont think there is a differance, just a preferancs

 

[heller792]

surley you would think that one pulls out more than the other

 

[lordofthereef]

surley you would think that one pulls out more than the other

Well, why would you think this? The only sure thing one pulls out more is water.

Another plus for wet skimming is easier cleaning. Very dry skimming produces a thick and nasty sludge. The wetter the skim, the more you empty the cup, but the less you end up having to scrub it clean IME.

 

[heller792]

doc that is

 

[heller792]

thanks lord and i see your point, on a dry skimm it takes longer to get waste in the cup but you get much more of a gunk were as with wet skimm its dillute and more often but over the same period of time it might only be the same amount of waste that they pull. hope ive made that clear.

Dave

 

[lordofthereef]

thanks lord and i see your point, on a dry skimm it takes longer to get waste in the cup but you get much more of a gunk were as with wet skimm its dillute and more often but over the same period of time it might only be the same amount of waste that they pull. hope ive made that clear.

Dave

Certainly clear enough for me!

I could be completely wrong about which method actually skims more. I am just going by what I have read. A lot of info in this hobby is scientifically acquired, but a lot is not. I am not sure if there is clearcut scientific data showing one way or the other. Hell, the skimmer you are using might even be a huge variable (in that some skimmers ay do better wet while others may do better dry).

 

[JMartin104]

An interesting question and one I've thought about myself. You might want to simply contact a company that makes skimmers (not just sell) and ask them. They should know if it makes any difference other than the obvious water.

 

[UnoZeus]

I cover my bases by going back and forth between wet and dry.

 

[slief]

I wet skim.. I find its easier to maintain the skimmer that way not to mention more consistant. Dry skimming usually results in more skimmer adjustments. With a wet skim, its more set it and forget it.

 

[evsalty]

Aqua C states this in their user manuals:

Wet vs. Dry Foam​

The decision to collect a watery, diluted waste product or a darker, pasty foam is a
matter of personal preference.​

Simply put, one is not better than the other! Wet​

foam contains the same amount of waste products as dry foam, but is diluted with tank

water. In other words, the skimmer is removing the same amount of waste whether it
collects a cupful of yellowish liquid or a ¼” of dark gunk. Depending on how often you​

clean and service your system, one might be better than the other.

 

[lordofthereef]

Thanks for that ev. I wonder if they actually gathered real data to come up with that conclusion.

 

[d0ughb0y]

Well, why would you think this? The only sure thing one pulls out more is water.

Another plus for wet skimming is easier cleaning. Very dry skimming produces a thick and nasty sludge. The wetter the skim, the more you empty the cup, but the less you end up having to scrub it clean IME.

i think dry skim will pull out more DOC.
if you go back to the basic principle of skimming (search foam fractionation), DOC are hyrophobic, hence will seek out air, and dry skim will use a lot more air than wet skim, ergo dry skim will pull out more DOC than wet skim given the same amount of time.


http://en.wikipedia.org/wiki/Protein_skimmer

Protein skimmer manufacturers go through the trouble of improving protein skimmer designs by introducing things like mesh wheel and needle wheel in or to increase the amount of air/water interface. Skimming wet completely defeats the purpose of efficient skimming.

 

[t4zalews]

I run my skimmer to skim a little dryer. I get good gunk out, but I also clean my collection cup and neck every 3-4 days to make sure my skimmer is running efficient.

 

[lordofthereef]

i think dry skim will pull out more DOC.
if you go back to the basic principle of skimming (search foam fractionation), DOC are hyrophobic, hence will seek out air, and dry skim will use a lot more air than wet skim

Will it though? (this is a serious question). I am not personally certain a dry skim is "using" more air than a wet skim.

 

[Palting]

Interesting read. I've had my own opiniion on the matter, and good to see other's thoughts as well. Thanks for that quote, evsalty.

Let's see if I can put it all together.

Dry skim or wet skim, they pull out the same amount of unwanted stuff over time. One is just more dilute, the other more concentrate.

Wet skim pulls out more saltwater. A good idea if you want to do a slow, almost continuous water change by replacing the lost volume with fresh saltwater. Also easier to clean. Have to make sure you don't end up raising SG, though, since you would also end up replacing evaporation with saltwater. Unless you have a two part ATO or something.

Dry skim has less saltwater, and you can maintain sump water levels with RODI water since you lose most of the water with evaporation. This time have to make sure your SG doesn't drop, since you are also replacing the skim water with RODI water. Again, unless you have a 2 part ATO or something . I do my skim REALLY dry, like day old coffee, and cleaning is not a problem as the thick junk just dissolves in running water, so I won't list cleaning as a problem.

Not sure about consistency, as someone has mentioned it makes a difference. It doesn't with me. I set the knob, and the skimmer consistently makes wet or dry skim however I set it. It maybe dependent on set-up or skimmer brand.

Does that about sum it up?